Control device for the laying rail of a warp knitting machine



July 22, 1969 P. R. OF'FERMANN ET AL 3,456,451

CONTROL DEVICE FOR THE LAYING RAIL OF A WARP KNITTING MACHINE Filed Nov. 15, 1967 6 Sheets-Sheet 1 r l I l I l l INVENTORS PETER RUDOLF OFFERMANN g SIEGFRIED WALTER PILZ A PETER ERICH SONNTAG July 22, 1969 R, bFF N ET AL 3,456,461

CONTROL DEVICE FOR THE LAYING RAIL OF A WARP KNITTING MACHINE Filed Nov. 15, 1967 6 Sheets-sheet 2 INVENTORS 2 PETER RUDOLF OFFERMANN e9 0| July 22, 1969 CONTROL DEVICE Filed Nov. 15. 1967 P. R. OFFERMANN ETAl- 3,

FOR THE LAYING RAIL OF A WARP KNITTING MACHINE 6 Sheets-Sheet 3 CONTROL DEVICE FOR was LAYING RAIL OF A WARP KNITTING MACHINE Filed NOV. 15, 1967 y 1969 P. R. OFFERMANN ET 6 Sheets-Sheet 4 NVENTORS PETER RUDOLF OFFERMANNeioI FIG. 5

July 22, 1969 P. R. OFFERMANN ET 3, 5

CONTROL DEVICE FOR THE LAYING RAIL OF A WARP KNITTING MACHINE Filed Nov. 15, 1967 i 6 Sheets-Sheet 5 INVENTORS PETER RUDOLF OFFERMANN et ul July 22, 1969 p QFFERMANN ET AL 3,456,461

CONTROL DEVICE FOR THE LAYING RAIL OF A WARP KNITTING MACHINE Filed Nov. 15, 1967 e Sheets-Sheet e INVENTORS PETER RUDOLF OFFERMANN et ul United States Patent CONTROL DEVICE FOR THE LAYING RAIL OF A WARP KNITTING MACHINE Peter Rudolf ()fiermann, Dresden, Siegfried Walter Pilz,

Cossebaude, and Peter Erich Sonntag, Heidenau, Germany, assignors to VEB Nahwirkmaschinenbau Malimo Karl-Marx-Stadt, Karl-Marx-Stadt, Germany Filed Nov. 15, 1967, Ser. No. 683,257

Int. Cl. D04b 15/66, 27/10 US. Cl. 66-86 14 Claims ABSTRACT OF THE DISCLOSURE A device for controlling the axial movements of a laying rail or guide bar, or guide rail of a knitting machine is disclosed. The control device comprises a first member which is axially displaceable in opposite directions to impart axial motion to said rail or bar, and a second member which is also axially displaceable in the same opposite directions as said first member and which may be selectively positively connected to the first member. The path of movement of the second member is limited on both sides by abutments. The device also includes means for selectively positioning the second member between the abutments independently of and relative to said first member while cams or a lever arrangement serve for imparting motion onto said first and second members when they are interconnected to thereby axially displace the rail or bar of the knitting machine.

Background of the invention The present invention relates to a device for controlling the displacing or offsetting movements of a guide bar (Legeschiene) of a warp knitting machine, especially a Raschel warp knitting machine. In such knitting machines, the adjusting means for effecting the movements of the rail cooperates with an arrestable intermediate member which receives the necessary stroke for displacing the rail from the adjusting means while the device furthermore comprises means for preselecting the stroke of the next displacing movement to be carried out, when the intermediate member is arrested.

By British Patent No. 888,702, a hydraulic control device has become known which is controlled by electrical impulses and which may be employed for effecting the movements of the rails of warp knitting machines. A driven member pivotally connected to a ratchet and employed to effect the movements of the rail is in communication with a hydraulic system. The ratchet in the form of a plunger has its major portion arranged in a chamber under fiuid pressure and has another portion which is displaceably mounted in a hollow cylinder extending from the chamber, While that end of the ratchet which is remote from the driven member is shaped to conform to the circumference of the cylinder. An arresting member is provided which is adapted to engage one of the teeth of the ratchet to thereby arrest the plunger in a certain position, if required, so that the driven member cannot impart a displacing movement or working stroke onto the rail. A liquid column is arranged in series with the plunger and has at its end a piston displaceable in the same cylinder. This last mentioned cylinder in turn has a connection with a strokepreselecting device in the form of a so-called adding and subtracting mechanism. As is well known in the art, this connection must include power amplifying or power storing elements.

The plunger is, during the operation of the device, arrested each time when the rail is to swing through the knitting needles, in other words when the latter is not "ice supposed to carry out any displacing or offsetting movements in axial direction. On the other hand, the arresting means disengages the ratchet when the rail is to be displaced axially. The hydraulic system effects the control of the arresting means. When the arresting means is disengaged, the piston connected to the stroke-preselecting device during a movement, for instance towards the right, transfers the imparted stroke onto the plunger via the liquid column, the position of the plunger being determined by that portion of the liquid column which is adjacent to or in contact with the plunger. For the return movement of the plunger upon disengagement of the arresting means, the pressure in the chamber is utilized while the piston causing the rightward movement of the plunger is displaced toward the left by a predetermined distance by the stroke-preselecting device.

In view of the provision of the hydraulic fluid between the piston and the plunger the reliability and accuracy and control behavior of the entire device is rather unsatisfactory. The main reasons for this lie in the danger of gaseous inclusions in the hydraulic fluid, in particular air, the compressibility of the liquid and the air therein and the inherent inertia of a hydraulic system. All these factors contribute to inaccurate adjusting movements of the rail and to low adjusting speeds.

In this connection it is to be kept in mind that in addition to inaccuracies due to compressibility other errors have to be added which arise from the fact that power amplifying or power storing elements have to be arranged between the stroke-preselecting device and the piston, which likewise add to the inaccurate movements of the rail since they include a plurality of elements under load.

It is, therefore, an object of the present invention to eliminate the above-described disadvantages of the heretofore known devices for controlling the offsetting or dis placing movements of a guide bar of a warp knitting machine.

It is another object of the present invention to provide a device of the type mentioned in the preceding paragraph which will be very accurate and fast in effecting the movements of the rail of the knitting machine.

Summary of the invention The objects underlying the present invention have been realized by a device which comprises a first and a second axially displaceable member. The second member is limited in its movement by abutment means and is adapted to be coupled to the first member effecting the rail movement proper and is also adapted to be adjusted independently of the first member between the abutment means by a. stroke-preselecting device.

In a preferred embodiment of the device, the first axially displaceable member for displacing the rail of the knitting machine has two jaws or arms pivotally connected to a connecting portion, the jaws being provided with teeth for engagement with the second axially displaceable member which is axially adjustable between the two limiting or abutment means independently of said first member.

Brief description of the drawing The invention is illustrated by way of example in the accompanying drawing, in which:

FIG. 1 is a side view of a first embodiment of a device for controlling the movements of guide bar or rail of a knitting machine;

FIG. 2 is a side view of another embodiment of a control device according to the invention;

FIG. 3 is a side view similar to that of FIGS. 1 and 2 but of a still further modified embodiment of the invention;

FIG. 4 diagrammatically illustrates the drive mechanism for the various elements shown in FIGS. 1 and 2;

FIG. shows a part of the drive mechanism of FIG. 4 in greater detail; and

FIG. 6 diagrammatically illustrates the structure of a portion of FIG. 3 in greater detail.

Detailed description of the preferred embodiments Referring now to the drawing in detail, the device shown in FIGS. 1, 2 and 3 comprises a first member 1, a second member 2 and a stroke-preselecting means 3. The first member 1 includes two plier-like arms 1a, 1 and a connecting portion the outer end of which forms a laying rail or guide bar or guide rail 4 of a knitting machine. If desired, the rail may form a separate part. Rail 4 is provided with a row of needles 4a. Arms 1a, 1b are pivotally connected to the connecting portion 10 and cooperate with two levers 5, 6 provided with rollers 5a, 6a. For purposes of closing the plier-like arm 1a, 1b cams 7, 8 are mounted on driven shafts 7a, 8a of the knitting machine, while the opening movement of the arms is effected by tension springs 9, 10. The device is furthermore equipped with an arresting member 11 which is controlled by an eccentric 12 and which arrests member 1 when the rail 4 does not have to carry out a displacing or offsetting movement, i.e. when the needles 4a pass through a further row of needles (knitting needles 4b).

An arm 13 connects the second member 2 with the stroke-preselecting member 3. An extension 15 merely serves for properly guiding a rod 14 extending into device 3. The stroke-preselecting device comprises a program carrier, preferably a pneumatic reading device 16, the working program of which is for instance determined by a punched card or punched tape, and also comprises a digital control member 19. A plurality of control tracks X to X, (only two being shown in FIG. 1) branch off from reader 16 and effect the programmed adjustment of the control member 19 via conduits 17 and 18.

According to FIG. 1, the device furthermore includes two members for axially displacing member 2, namely two cams and 21 which are drivingly connected to the main machine shaft 26 (FIG. 4) of the knitting machine and which rotate with the same speed as the latter. Both cams rotate continuously, regardless of which cam is to carry out the next displacing stroke for member 2. Well known means are provided in the knitting machine for continuously establishing a driving connection between the main machine shaft 26 and the two earns 20, 21.

The control device according to FIG. 1 operates as follows: In the position shown, the needles 4:: are about to complete their movement through the row of knitting needles 4b. In order to prevent a movement of the rail 4 in axial direction, during the movement of the needles 4a through the row of knitting needles 4b, the arresting member 11 prevents movement of portion 10. The arms 1a, 1b have been opened during the movement of the needles 4a so that member 2 could be displaced. This was effected by stroke-preselecting device 3 in conformity with the program fed through reader 16, by displacing member 2 towards the right towards cam 21 by a predetermined amount. Now the arms 1a, 112 have to be closed in order to establish a positive, reliable connection between the first and second members via the serrations 27. In view of the rotating movement of cam 21 rail 4, upon completion of the passage of needles 4a through the row of knitting needles 4b, carries out a displacement movement towards the left. Rollers 2a, 2b serve for reducing the friction between the member 2 and cams 20, 21. Before a movement of member 2 can be effected, of course, arresting member 11 has to be disengaged from connecting portion 10, by rotation of cam 12.

Compressed air is used for transmitting the impulses originating in the reader 16 to member 2. This compressed air passes through passages 17, 18 and act upon the digital control member 19 and displaces rod 14 to a corresponding extent. During the displacing movement of rail 4 no compressed air acts on control member 19. Upon completion of the displacing movement of rail 4 portion 1c of member 1 is again arrested and the entire device is ready for the next control movement. If the rail is again to be moved towards the left, member 2 is again displaced towards cam 21, which can be repeated several times until rail 4 has reached its left hand end position.

For a displacing movement toward the right, member 2 is displaced toward cam 20. The starting position for element 2 is its center position between earns 20 and 21. The combination of the various adjusting possibilities for member 2 yields the advantage that any desired change in direction of the movement of the rail can be made and that any desired stroke within the end positions of rail 4 can be selected.

FIG. 4 illustrates more in detail the drive mechanism for effecting the movement of cams 7, 8, 12, 20 and 21 of FIG. 1 and 20a, 21a of FIG. 2. Main machine shaft 26 carries a gear 26a which is in driving engagement with a gear 26] having the same diameter and mounted on an intermediate shaft 26b. In order to establish a driving connection between cam 8 and shaft 26b, the latter carries a single sprocket wheel 26c driving a double sprocket wheel 8b fixedly connected with cam 8, via a chain 261'. Cam 12 is driven by a chain 26k passed over sprocket wheel 8b and a further double sprocket wheel 12a fixedly mounted on cam 12. Finally, double sprocket wheel 12a transmits its movement to cam 7 via a sprocket Wheel 7b and a chain 261. For purposes of driving earn 21 intermediate shaft 26b carries a single sprocket wheel 262 which cooperates with sprocket wheel 21!). The movement of cam 20 is effected by sprocket wheel 26d via a chain 26m and a sprocket wheel 20b. Sprocket wheels 20b and 211) are fixedly connected to the cams 20 and 21 respectively.

In the driving mechanism for driving a control device according to FIG. 1 the sprocket wheels 26d and 26e are fixedly connected to'intermediate shaft 26b (in contrast to the arrangement of FIG. 2 which will be described further below).

In the arrangement according to FIG. 2, the cams 20a, 21a are driven by the main machine shaft, as was the case in the embodiment of FIG. 1, and rotate at the same speed as the main machine shaft. However, both cams do not rotate continuously, but only that one of cams 20a, 21a which carries out the respective offsetting or displacing movement. Therefore, either cam 20a, 21a may be coupled to or disconnected from the main machine shaft, as the circumstances may require. This process is controlled by a special track 25 of reader 16, which track leads to a power switch 22 whereby alternatively the electromagnetic clutch indicated by arrows 23 and 24, respectively, is actuated. The impulse required for actuating one or the other of the clutches 23, 24 is caused or initiated by the main machine shaft 26.

The arrangement according to FIG. 2 operates basically in the same manner as that of FIG. 1, the only exception being that the cams 20a, 21a have a different control mechanism.

In the embodiment of FIG. 2, the sprocket wheels 26d and 26e are freely rotatably arranged on intermediate shaft 26b while the latter also receives two coupling or clutch portions 23 and 24 indicated in dash lines in FIG. 4, and shown in greater detail in FIG. 5 in combination with the power switch 22. Clutch portions 23 and 24 are shown in simplified form in side view in connection with the sprocket wheels 26d and 26a. Each sprocket wheel consists of a gear ring and a disc connected to the gear ring by springs. Consequently, each sprocket wheel 26d, 26e forms a system which can freely rotate on shaft 261). between sprocket wheels 26d and 260 there are located the two coupling or clutch portions or halves 23, 24. Both are formed by magnets and, in operation, are adapted to attract the sprocket wheels 26d, 2612. Since the two coupling portions 23, 24 operate alternately, there exists a driving connection either between the sprocket wheel 26d and the intermediate shaft 26b or between the sprocket wheel 26e and the intermediate shaft 26b. The driving connection is established by one of the sprocket wheels 26:! or 26e adhering to the end face of one of the coupling portions 23, 24. Reference numerals 26g designate adjusting rings. serving as abutments.

Assuming that a sufiiciently strong impulse is fed to the diaphragm relay A from reader 16 via control conduit 25,"relay A will close electric contacts. By actuating relay A, a control relay B is attracted which is subjected to a very weak voltage U Thus relay B closes a working circuit operated with voltage U and including coupling portions 23, 24. Portions 23, 24 are provided with coils C and D respectively receiving one iron core each. The flux of the circuit is transferred to the coils C and D by the sliding contacts E, F and G. Therefore, assuming that a pneumatic impulse is fed to power switch 22, magnetic coil D will attract sprocket wheel 26e and hold against its end face to thereby establish a driving connection between intermediate shaft 2611, the sprocket wheel 26e and the cam-21a.

Assuming that no impulse is fed into switch 22 via reader 16, relay A is open and relay B is no longer attracted, i.e. in a position in which the circuit for the coupling portion 23 is closed. Therefore, sprocket wheel 26d is attracted and the intermediate shaft 26b is drivingly connected to the cam 20a. Depending on the operation of reader 16, consequently one or the other driving connection is possible and also a non-continuous change from the actuation of one coupling portion to the other or vice versa.

In the embodiment according to FIG. 3, the cams have been replaced by stationary abutments 28, 29 against which member 2 will abut at the completion of the offsetting or displacing movement. The movement itself is carried out by a hydraulically or pneumatically operated oscillating member 30 which has its free end guided in a passage 31 of portion of member 1. The pivot point of oscillating member 30 is located at bearing 32. Two pistons 33, 34 act upon member 30 which in turn are acted upon by a fluid in cylinders 33a, 34a. The direction of movement and the length of the strokes of pistons 33, 34 is predetermined by a power switch 35 from which two conduits 36, 37 branch oif to the cylinders 33a, 34a, respectively. Also in this instance, the special track 25 pre-selects the direction of movement of the oscillating member 30. The forces exerted by pistons 33, 34 are adapted to the entire device, while springs 38, 39 serve as cushions and make possible a constant or equal stroke of the pistons 33, 34. Power switch 35 has associated therewith a fluid inlet valve 40 which is opened by an impulse sender 41 when a cam 42 mounted on the main machine shaft 43 gives a corresponding signal. Cam 42 gives this signal always at the start of the displacing or offsetting movement.

FIG. 6 illustrates in greater detail the structure of power switch 35. In contrast to the arrangement described in connection with FIGS. 3 and 5 relay B has associated therewith a control slide H which closes the conduit or passage 37 if the relay B is not attracted. Slide H is arranged in a cylinder H.

Cam 42 (see also FIG. 3) is driven by main machine shaft 26 through the intervention of gears 26h and 42a. Impulse sender 41 is continuously lifted or lowered thus controlling the supply of fluid under pressure to inlet valve 40.

It may be mentioned that while the pneumatic reader 16 may have a variety of different forms, tests have shown that the one described for instance in French Patent No. 1,473,019 has proved very successful. The digital adjusting member or control member 19 is preferably designed as a simple pneumatic piston.

In view of the fact that the two displacing members 1 and 2 are positively coupled to each other and in view of the particular design of the displacing members as described above, reliable and accurate adjusting movements of the rail of the knitting machine are assured. It is particularly advantageous that the means which preselect the stroke of the offsetting or displacing movement of the rail are under a small load since member 1 carrying out the actual displacing movement is not connected to member 2 during the preselecting operation. Summarizing the advantages of the arrangement according to the present invention, a considerable improvement in the control behavior with regard to heretofore known devices has been achieved.

While preferred embodiments of the invention have been described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, to be understood that the invention is only limited by the scope and spirit of the appended claims.

What is claimed is:

1. A device for controlling the axial movements of a laying rail of a knitting machine, which comprises: an intermediate member axially displaceable in opposite directions and connected with said rail to impart its motion thereon, an adjustment member axially displaceable in the same directions as said intermediate member and disposed in operative proximity with the latter, controllable arresting means for said intermediate member, coupling means for selectively connecting and disconnecting said intermediate and adjustment members, means arranged in the path of movement of said adjustment member for limiting the axial movement thereof in said opposite directions, preselector means for selectively axially positioning according to a program said adjustment member between said limiting means during the blocking position of said arresting means, and means for imparting axial motion on said adjustment member upon interconnection thereof with said intermediate member.

2. A device according to claim 1 wherein said coupling means includes two arms pivotably connected with said intermediate member on opposite sides of said adjustment member.

3. A device according to claim 2, wherein said arms are provided with teeth for gripping engagement with said second member.

4. A device according to claim 2, wherein said coupling means further includes lever means adapted to bring said arms into engagement with said adjustment member.

5. A device according to claim 2, in which one of said limiting means is located between said arms.

6. A device according to claim 1, wherein said preselector means for selectively positioning said adjustment member between said limiting means comprises a digital control member, and a pneumatic reader for transferring signals of a program to said digital control member.

7. A device according to claim 1, wherein said limiting means and said motion imparting means are integrally formed.

8. A device according to claim 1, wherein said motion imparting means includes a pivotally supported oscillatable member engaging said intermediate member, two piston means connected to said oscillatable member for imparting motion thereon in opposite directions, power switch means for selectively actuating one of said piston means at a time and a pneumatic reader for transferring signals of a program to said power switch means for actuating said selective piston means.

9. A device according to claim 1, wherein said motion imparting means includes rotatable cams arranged at opposite ends of said second member.

10. A device according to claim 9, which includes means for selectively driving only one of said cams at a time.

11. A device according to claim 10, wherein said selective driving means comprises a power switch, a reader, means interconnecting said reader and said power switch and adapted to transmit signals from said reader to said power switch, and means connecting said power switch to said rotatable cams for selectively driving one of said cams at a time.

12. A device according to claim 1, wherein said limiting means are formed by stationary abutments.

13. A device according to claim 8, wherein said power switch means is adapted to impart a constant stroke onto said piston means.

14. A device according to claim 7 wherein said limiting means are two rotating elements disposed in operative proximity opposite to the ends of said adjustment member, and said motion imparting means are cams provided on said elements for alternatively driving said adjustment member in one of said opposite directions.

References Cited FOREIGN PATENTS 12/1956 France.

1/1930 Germany. 1/ 1962 Great Britain. 1/1962 Great Britain.

15 RONALD FELDBAUM, Primary Examiner U.S. Cl. X.R. 

